Thread-drawing machine



Feb. 26, 1935. H. GUNTHER THREAD DRAWING MACHINE Filed June 8, 1934 .3 Sheets-Sheet l Feb. 26, 1935. H. GUNTHER THREAD DRAWING MACHINE Filed June 8, 1934 5 Sheets-Sheet 2 Hermann Gunifi em Feb. 26, 1935. H. GUNTHER 1,992,370

THREAD DRAWING MACHINE Filed June 8, 1934 3 Sheets-Sheet 3 Patented Feb. 26, 1935 UNITED STATES 1,992,370 7 THREAD-DRAWING MACHINE Hermann Gunther, Elizabeth, N. J., assignor. to

The Singer Manufacturing Oompan'm. Elizabeth, N. J., a corporation of New Jersey Application June 8, 1934, Serial No. 729,625

' 17 Claims; (01. 112-78) This invention relates to machines for draw ing threads in fabrics to be hemstitched.

A machine forthis purpose commonly comprises a framewhich'maybe constructed with a 5 bed and gooseneck similar to a sewing machine frame and which is fitted with operatively connected upper and lower rotaryshafts, fabric-feeding mechanism including a feed-dog, a springpressed presser-bar with one or more presser-feet, 10 a throat-plate, a vertically reciprocatory piercerbar carrying a spear-like piercer blade having fine saw-toothed thread-drawing edges-and adapted to penetrate the work and push the; longitudinal threads downwardly through a slot in the throatl5 plate transverse to the line of feed, and a rotary cutter carried by the lower rotary shaft and having a cutting edge transverse to the line .of feed for cutting off the drawn threads.

Considerable difliculty has been experienced in 20 adapting machines suchas heretofore constructed to the drawing of threads of wide zones of the order of A; inch, due to the tendency of a piercer blade of this width to push both the transverse and longitudinal threads of the fabric-down into the field of action of the cutter, with the result that damaging holes are cut in the work. To

avoid this, various expedients have been proposed to laterally spread or tension the fabric so that the transverse threads will be heldunder strain and prevented frombeing carried downwardly by the piercer blade. Noneof the expedients heretofore proposed has proven to be entirely satisfactory-for use with wide thread-drawingpiercers, or for work from which the threads are to be drawn 35 closeflto; sayi ig o'ffan inch' fromthe edge thereof.

The present invention haslfor an object to provide athreadedrawing machine with simplified and improved mechanism for spreading or laterally: tensioning the work, 3 which mechanism 4 is effective when drawing threads from airelativelywidezone' or. path in the work or from a 'zone' or path close to the edge of the work. With the above and other objects in view, as will hereinafter appear, the invention comprises 45 the devices, combinations; and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred-embodiment of the invention, from which the several features of the invention and the advantages at- .50 tained thereby. will be readily understood by those ,skilled in the art. y

,In the accompanying drawings, Fig. 1 is a vertical longitudinal sectional view of a threaddrawing machine embodying the invention. Fig.

55 2 is a bottom plan view and Fig. 3 is anend elea purpose to be described. The piercer-blade may to vation of the machine. Fig. 4 is a front elevation, partly in section, of the presser-foot and work-spreading mechanism with i the piercerblade at its highest point. Fig, 5 is a similar View with thepiercer blade at its lowest point. 5 Figs. 6 and 7 aresections on the lines 6-6 and 77, respectively, Fig. 5. Fig. 8 is a horizontal section through the piercer-blade clamp on the .piercer-bar. Fig. 9 is abottom plan view of the presser-foot. Fig. 10 is a top plan view of the 10 throat-plate and Fig. 11 is a disassembled perspective view ofthe presser-foot.

, The frame of the machine is like the frame of anordinary sewing machine and comprises a flat bed 1 and standard 2 ofan Overhangingbraoket- .15

arm 3 terminating in the head 4. Journaled in the bracket-arm 3 is the mainshaft 5 having at its front end a crank 6 which is connected by the link 7 to the reciprocatory piercer-bar 8 carrying the piercer-blade 9. V 20 The piercer comprises the'usual flat spear like head with serrated upwardly divergent edges carried by the'cylindrical' shank 9 which is clamped against the bottom wall- 10, Fig. 8, of a lateral slot 11 in the piercer-bar 8 by means of .a clampscrew 12 carried by a collar 13 surrounding the piercer-bar 8 and fixed to the latter by means of aclamp-screw 14. The collar 13 carries a rearalso be adjusted rotativelyby loosening the setscrew 12, without disturbing the'adjustment of the collar 13 and its roller stud 15 upon the piercer-bar 8. 1

t The main-shaft 5 drives the vertical shaft 16 4 through the one-to-one bevel gears 17. and the vertical shaft 16 drives the lower rotary shaft18 through the one-to-one bevel gears 19. The lower rotary shaft18 carries the usual rotary cutter blade 20 having an'inclined sharpened cutting 45 edge 21 which shears off the drawn threads in cooperation with'the forward lower edge 22 of the piercer-slot'23 in the throat-plate 24.

- The throat-plate 24 is also provided with the usual lateral feed-dog clearance slots 25, 25 for the lateral feed-dog sections 26, 26 and with the front and back central feed-dog clearance slots 27, 27 for thecentral feed-dog sections 28, 28. Y

- The feed-dog sections 26 and'28 are integrally related and carried as usual by the feed-bar 29, Fig. 5

: spring-pressed presser-bar 41 to which is detachthe Work as their spread increases.

ably secured by means of a screw 42 thepresserfoot shank 43 in the lowerend of which is horizontally journaled the bearing stud 44 fixedly seured to the carrier 45 which has two laterally spaced and forwardly extending arms 46, 45

carrying the horizontal pivot-screws 47, 47 for the sole-piece 48, which is thus free to tilt universally relative to the shank 43.

The carrier arms 46 of the presser-foot have vertical ways 49 formed therein to receive the vertical positioning ribs 50 of the independently vertically adjustable extension-plates 51 held in adjusted position by screws 52 which pass through oversize clearance holes 53 in the respective extension-plates 51.

Pivotally attached to the upper ends of the vertical extension-plates 51 by screws 54 are the depending fingers 55 formed at their lower ends with forwardly extending work-engaging extremities 5 6 having slightly roughened lower work-engaging faces 57, Fig. 9, adapted'to engage the work exposed by the rectangular aperture 58 in the presser-foot sole-plate48. The

plates 51 are adjusted on the carrier arms 46 so that the work-engaging faces 57 of the workspreading fingers 55 project slightly and sufficiently below the level of the lower face of the presser-foot sole-plate 48 to engage and spread the work.- v

The fingers 55 are biased inwardly into engagement with the stop-pin 59 by means of the springs 60' whichare supported bythe. screws 61. The lower horizontal extremities 56 of the fingers are formed with clearancenotches 62 for the piercerblade 9.

It will be observed in Fig. 4 that when the fingers are in engagement with the stop-pin 59, the inner edges of the fingers diverge upwardly at opposite sides of the roller stud 15 on the piercerbar. As the piercer descends the feed-dog drops below the throat-plate. The presser-foot and work-spreading fingers 55 press the work upon the throat-plate with the fingers 55 in their inner positions. Just before the point of the piercer reaches the fabric the roller stud 15 simultaneously engages the inner edges'of the fingers 55 and initiates the work-spreading movement-which continues until the piercer reaches its lowest point, Fig. 5; the fingers 55 slipping over the fabric but having sufficient grip thereon to laterally spread or tension the fabric so that the crossthreads thereof will not be carried down by the piercer-blade. Moreover, it will be observed that the arcs of motion of the work-engaging extremities of the fingers 55 about their respective pivots 54 are outwardly. and downwardly, thus increasing the grip or drag of the fingers 55 upon In the fully spread'positions of the fingers 55 their work-en? gaging faces are substantially or so nearly vertically below their respective pivots that they remain'in their spread positions and hold the fabric andcross-threads under lateral tension as the piercer rises and until its point is clear of the work and the rotary knife has passed its cutting position and severed the drawn longitudinal threads. The feed-dog then rises and lifts the fabric and presser-foot from the throat-plate, whereupon the springs 60 return the fingers to their inner positions against the stop-pin 59.

7 Because of the continuous spreading action of the fingers 55 during the descent of the piercer through the fabric, it is possible to use piercerbla'des of considerable width, say A; inch, without damage to the fabric. Furthermore, by applying the spreading fingers to the fabric close to the piercer, and by using center feed-dog sections as well as the side feed-dog sections it is possible to draw threads as close as may be desired to the edge of the fabric.

The roller-stud 15 may be lubricated by means of an oil-saturated felt wick 15', Fig. 3, which may be suitably supported in position to be engaged by the roller-stud 15 as the latter ends its up-stroke. I

The collar 13 should be so adjusted or set'on the piercer-bar 8 that the roller -stud'15'will act simultaneously and equally on the spreading fingers 55. j r

The invention is not to be understood as limited to the specific forms and arrangements of parts shown and described as such forms and arrange-T- ments are merely illustrative of one embodiment of the invention from which the principles of the invention will be readily understood and may obviously be embodied in a variety of forms by those skilled in the art.

Having thus set forth the nature tion, what I claim herein is:

1. In a thread-drawing machine, the combination with a piercer-blade, a reciprocatory piercer-bar carrying said blade, a feed-dog, and a presser-foot, ofmeans actuated by said piercerbar to spread the work laterally of the line of feed.

2. In a thread-drawing machineythe combination with a piercer-blade, a reciprocatory piercerbar carrying said blade, 2. feed-dog, and a presserof the invenfoot, of separable means actuated simultaneously.

in opposite directions by said piercer-bar to spread the work laterally of the line of feed.

3. In a thread-drawing machine, the combination with apiercer-blade, a reciprocatory piercerbar carrying saidblade, a feed-dog, and a presserfoot, of means movable laterally of the line of feed and actuated by said piercer-bar 'on the down-stroke of the latter to spread the work.

4. In a thread-drawing machine, the combination with a piercer-blade, a reciprocatory piercerbar carrying said blade, a feed-dog, and a presserfoot, of work-spreading means mounted on and movable relative to said the line of feed.

5. In a thread-drawing machine, the combination with apresser-foot having an apertured and universally tiltable sole-plate, of'work-spreading fingers pivotally carried by the presser-foot and having work-engaging extremities disposed in the aperture in said sole-plate.

6. In a thread-drawing machine, the combination with a presser-foot having an apertured and universally tiltable sole-plate, of work-spreading fingers pivotally carried by the presser-foot and having work-engaging extremities disposed in the aperture in said sole-plate, means for simultaneously moving said fingers away from one another to spread the work, and spring means for imparting recovery movements to said fingers.

presser-foot laterally of 7. In a thread-drawing machine, a presser-foot having an apertured sole-plate, and a pair of depending work-spreading fingers pivotally mounted at their upper ends on said presser-foot and adapted to engage the work exposed Within the sole-plate, said work-spreading elements being independently vertically adjustable.

10. In a thread-drawing machine, a reciprocatory piercer-bar, a piercer-blade carried thereby, a feed-dog, a presser-foot having a sole-plate, a pair of pivoted and depending work-spreading fingers, and a stud carried by said piercer-bar in position to engage and spread said fingers on the down-stroke of said bar;

11. In a thread-drawing machine, a presserfoot, a vertical spring-pressed presser-bar,. a throat-plate, a feed-dog, a pair of depending work-spreading fingers pivoted at their upper ends to said presser-foot and having roughened work-engaging surfaces at their lower ends, a reciprocatory piercer-bar, a piercer carried thereby, and means for spreading said fingers on the down-stoke of said piercer-bar.

12. In a thread-drawing machine, a presserfoot, a vertical spring-pressed presser-bar, a throat-plate, a feed-dog, a pair of depending work-spreading fingers pivoted at their upper ends to said presser-foot and having roughened work-engaging surfaces at their lower ends, a reciprocatory piercer-bar, a piercer carried thereby, and means for spreading said fingers on the downstroke of said piercer-bar, the work-engaging surfaces of said fingers being substantially vertically below their respective spread position of said fingers.

13. A thread-drawing machine having a reciprocatory spear-like piercer, a cutter, a feed-dog, a presserfoot, and work-engaging means moving laterally of the line of feed during the descent of the piercer through the work for spreading therwork.

14. ,A thread-drawing machine having a reciprocatory spear-like piercer, a cutter, a feed-dog, a presser-foot, and laterally and downwardly movable pivoted means carried by said presserfoot for exerting a continuously increasing spreading grip upon the fabric as the piercer descends through the latter.

15. A thread-drawing machine having a reciprocatory spear-like piercer, a cutter, a. feeddog, a presser-foot having an aperture therein through which the piercer operates, and laterally movable fabric-spreading means for engaging the work in said aperture closely adjacent said piercer.

16. In a thread-drawing machine, a reciprocapivotal axes in the i tory piercer, a complementary cutter, fabric feed:

ing mechanism, a pair of fabric spreading elements initially in engagement with the fabric in the path of the piercer, and means for spreading said elements as the piercer descends.

17. In a thread-drawing machine, a'reciprocatory piercer, a complementary cutter, fabric feeding mechanism, a pair of fabric spreading elements, and means for moving said elements simultaneously in opposite directions as the piercer descends.

HERMANN GUN'IHER. 

